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Re: Water waves



Yes, the source or generator of the wave determines the orientation, but in
far field the character of the medium and the type of wave predominates. The
original writer referred to the orientation resulting from refraction due to
an undersea slope. I have observed this many times from the UCSB bluff
overlooking Goleta beach . the waves travel nearly parallel with the coast
off shore. By the time they reach the beach, they travel perpendicularly to
the beach. The refraction is obvious.

some sites from a google search (refraction water waves ocean) :

http://www.brookes.ac.uk/geology/8361/1998/craig/craig.html

This one has formulae:

http://intra.es.lancs.ac.uk:8080/gs/GEPH323/CW98/O_Barton/shallowwaterwaves.htm

though about an unusual type of wave, refraction applies


http://www.geophys.washington.edu/tsunami/general/physics/characteristics.html

bc


Jim Green wrote:


Water waves with larger wavelengths use gravity as a restoring force,=
these being called gravity waves.


and IIRC the speed of this second kind is strongly depth dependent as
shown by ocean waves arriving at shore in a fairly 'parallel to
shore' orientation.

Umm, I duno. Maybe, but ocean tidal waves are born in ocean basins. I
think that the waves would be oriented with respect to the basin. The
_surface waves_ would be oriented with respect to the _prevailing winds_
and in this case reasonably parallel to the general shape of coast line.
The Black Sea would be my first example -- the tidal waves there are
circular and, on the north and south coasts are perpendicular to the
coastline. What would interest me at this point is whether the surface
waves were parallel to the coasts there -- presumably due to the prevailing
winds.

Jim Green
mailto:JMGreen@sisna.com
http://users.sisna.com/jmgreen